dd:tldr:9f6b5

The dd command is a data copying tool in Unix-like operating systems, commonly used for low-level disk operations. Here's a breakdown of the command you provided:

• dd: This is the command itself.

• if=${-dev-source_drive}: The if flag specifies the input file or device to copy from. In this case, it uses the ${-dev-source_drive} variable to represent the source drive, where ${-dev-source_drive} is likely a placeholder for the actual device path (e.g., /dev/sda or /dev/disk0).

• of=${-dev-dest_drive}: The of flag specifies the output file or device to copy to. Again, it uses the ${-dev-dest_drive} variable to represent the destination drive.

• bs=${4M}: The bs flag specifies the block size to copy at a time. In this case, ${4M} represents a block size of 4 megabytes. It determines how much data is read from the source drive and written to the destination drive in one operation.

• conv=${noerror}: The conv flag specifies various conversion options during the data copying process. ${noerror} is likely a variable that disables error checking, allowing dd to continue copying even if it encounters read errors.

• status=progress: The status flag provides progress information during the copying process. In this case, it displays the progress in terms of bytes written and the transfer rate.

Overall, this command uses dd to copy data from the source drive to the destination drive, using a block size of 4 megabytes, ignoring read errors, and showing the progress of the operation.